As people replace face-to-face meetings with longer distance communications, the need for providing security in those technology-based communications has become more pronounced. It has long been accepted that telephone communications via plain old telephone service (POTS) is a relatively secure communication service in view of the fact that it is considered illegal to intercept or tap into communications over these wireline networks. The network providers themselves provide a high degree of security for the communication. By contrast, alternative techniques for communication are more susceptible to security leaks. For instance, wireless communications, such as mobile telephony or a service referred to as “fixed wireless”, rely on air links between communicating terminals. These airlinks by their very nature are not secure. While aggressively copying information from the air waves may be considered inappropriate and illegal, the mere detection of that information is not. Privacy or expectations of security are not regularly attributed to such wireless communications. Furthermore, certain data communications, such as those which are routed on the Internet via various router devices, may also be considered to be susceptible to privacy leaks.
Where the communication medium is susceptible to security breaches, it is beneficial to provide some technique for improving the security of the messages transmitted over the medium. In particular, one such technique involves encrypting messages before they are transmitted and decrypting them at the receiving communication terminal. Various encryption techniques are known and available. Where the data is stream-like in nature, it may be possible to use block-type encryption such as the Data Encryption Standard (DES) (Federal Information Publishing Standards, FIPS Pub. 46). This typically requires the use of an Application Specific Integrated Circuit (ASIC) because it can be computationally intensive. Alternatively, where there is a high degree of synchronization between a pair of communication terminals, it might be possible to use a more robust stream type encryption method such as that referred to as RC4 encryption. RC4 was developed by RSA Data Security Incorporated. This encryption technique is very robust and is not computationally intensive.
Some encryption techniques require that the encryption engines in the communicating terminals be synchronized since the encryption/decryption key is designed to vary over the passage of time. The RC4 encryption process is one such encryption technique. Not all of the communication media for which encryption is desirable are easily adaptable to the synchronization needs of the synchronous encryption methods such as RC4. It would be beneficial if there was a way, in for instance a packet data transfer environment, that such synchronization could be provided to enable deployment of a lightweight encryption/decryption method such as RC4.